Multi-variable thermal design of T-structured phase-change memory cell using advanced response surface method

Thermal design is crucial in designing phase-change memory (PCM) as it is operated by thermal energy. Among the numerous factors that influence the performance of PCM, geometrical configuration is the most critical factor as the heat confinement is determined by the effective thermal resistance of the PCM cell. This study reports the thermal design of T-structured PCM cell with contact diameter of 80 nm. Five design variables, which are the thicknesses of two metal contact layers, two metal electrode layers, and one phase-change layer, are studied. Cell performance is evaluated in terms of the highest cell temperature during the reset process. The performance results of the five variables are correlated into a single equation using the advanced response surface method, which is a modified form of conventional response surface method. By doing this, one can easily design and define the PCM with the best performance under given constraints. Given design ranges, results show that the cell performance is maximum when the two top metal layers and the bottom metal electrode become thinner while the bottom metal contact becomes thicker. However, there exists a certain phase-change layer thickness, which is 36 nm in this study, for the maximum performance to occur.